NB1A Real-Time Clock

NB1A RTC Files

NB1A RTC Example

This program initializes the DS1337 real-time clock (RTC) to output a time and date string every second to the serial port. Until the DS1337 is set for the first time (or reset after a battery change) the time registers will be set at zero. The code in the following example will initialize the date to August 25th, 2009 and the time to 3:00PM.


// initialize the date to August 25th, 2009

rtc.set_date(2009, 8, 25);

// intialize the clock to 3PM

rtc.set_time(15, 0, 0);

NB1A RTC Example

#include <avr/interrupt.h>    
#include <avr/io.h>  

#include <LED_debug.h>
#include <TWI.h>
#include <RTC.h>

#define int_enable   PCICR  |= (1 << PCIE1)
#define int_disable  PCICR  &= ~(1 << PCIE1)

LED_debug led;
RTC rtc;

void setup() {

  // Compensating for the 12MHz XTAL
  // 12800 = (16/12) * 9600
  // 25600 = (16/12) * 19200

  Serial.begin(12800);

  // setup the TWI 

  TWBR = TWI_TWBR;                         // Set bit rate register (Baudrate). Defined in TWI.h  
  TWDR = 0xFF;                             // Default content = SDA released.

  TWCR = (1<<TWEN)|                        // Enable TWI-interface and release TWI pins.
         (0<<TWIE)|(0<<TWINT)|             // Disable Interupt.
         (0<<TWEA)|(0<<TWSTA)|(0<<TWSTO)|  // No Signal requests.
         (0<<TWWC);

  int_enable;

  // initialize the date
  rtc.set_date(2009, 10, 14);

  // intialize the clock
  rtc.set_time(9, 4, 15);

}

void loop() {
  char timestr[22];
  while(1) {
    rtc.read_regs();
    rtc.localtime(timestr);
    Serial.print(timestr);
    Serial.print("\n");
    led.blink(2); 
    delay(1000);
  }
}